Animated tale, produced by a staff of Disney-trained artists led by "American Tail's" Bluth; concerns a newly widowed mouse who discovers a secret agency of superintelligent rats (they've escaped from a science lab) who aid her in protecting her family. As is usually the case with Bluth films, the animation is superb while the socially aware plot struggles to keep pace. That aside, it's still an interesting treat for the youngsters. Adapted from Robert C. O'Brien's "Mrs. Frisby and the Rats of N.I.M.H."